thinkso

Not sure about HDB allowed or not. But did asked for quotes to shift toilet bowl before - $2k. Its too expensive to shift, so suggest not to shift at all. Cheaper choice, maybe to choose a smaller size toilet bowl.

Yes, can do but that time when i did mine, some of the contractors will request to see your toilet before they advise you. Let them advise you, just get a few quotes to compare. My waterproofing is around $150 for the toilet, seems like a standard rate. Out of all, only 2 of the contractors have workers that undergo waterproofing certification. Just take it as a reassurance that the waterproofing is not done by random workers, by the time problems come back, the warranty is over.